Field of Invention
This invention relates to electrocautery surgical instruments and more particularly to an electrocautery scalpel system having variably extendable suction and electrode elements to facilitate electrocautery surgery at deep locations within surrounding tissue.
Electrocautery instruments commonly rely upon high-voltage, high-frequency electrical signals of various waveforms to selectively sever, clamp or coagulate living tissue during surgical procedures. In addition, many such electrocautery instruments include integral vacuum conduits and associated suction apparatus for evacuating tissue fluids and volatized tissue materials that commonly accompany electrocautery incision of living tissue. Devices of these types are disclosed in the literature (see, for example, U.S. Pat. Nos. 1,311,494; 1,963,636; 2,002,594; 2,894,512; 3,662,151; 3,682,162; 3,828,780; 3,835,842; 3,850,175; 3,884,237; 3,902,494; 3,906,955; 3,974,833; 3,987,795; 4,011,872; 4,112,950; and 4,562,838; and French Patent No. 73.30854). Electrocautery instruments of these types also commonly employ a retractable electrode or a vacuum port to enhance the utility of the instrument during surgical procedures. One difficulty encountered with certain electrocautery scalpels having extendable and retractable electrodes is that the geometry of the instruments usually limits the depth in tissue to which the instruments can conveniently penetrate without expanding the incision to accommodate the surgeon's hand. As certain surgical procedures progress and penetrate deeper into a surgical site, it is frequently desirable to extend the instrument to longer dimension with control over the retractable electrode in order to facilitate advancing the surgery into deep, confined sites.